1 // SPDX-License-Identifier: GPL-2.0
6  * 12-bit ADC interface.
12  * This driver supports input common-mode voltage, current-sense
16  * Op-amp, analog comparator, and watchdog functionalities are not
58  *     (((adc_read >> 4) - offset) / ((1 / LSB) * 10^-3)
72  *     (((adc_read >> 4) * 1000) - offset) / (1 / 14 * 1000)
114  * max9611_mux_conf - associate ADC mux configuration with register address
137  * max9611_csa_gain_conf - associate gain multiplier with LSB and
195  * max9611_read_single() - read a single value from ADC interface
202  * Data are transmitted with big-endian ordering: MSB arrives first.
218 	 * Keep mutex lock held during read-write to avoid mux register  in max9611_read_single()
219 	 * (CTRL1) re-configuration.  in max9611_read_single()
221 	mutex_lock(&max9611->lock);  in max9611_read_single()
222 	ret = i2c_smbus_write_byte_data(max9611->i2c_client,  in max9611_read_single()
225 		dev_err(max9611->dev, "i2c write byte failed: 0x%2x - 0x%2x\n",  in max9611_read_single()
227 		mutex_unlock(&max9611->lock);  in max9611_read_single()
235 	ret = i2c_smbus_read_word_swapped(max9611->i2c_client, reg_addr);  in max9611_read_single()
237 		dev_err(max9611->dev, "i2c read word from 0x%2x failed\n",  in max9611_read_single()
239 		mutex_unlock(&max9611->lock);  in max9611_read_single()
244 	mutex_unlock(&max9611->lock);  in max9611_read_single()
250  * max9611_read_csa_voltage() - read current sense amplifier output voltage
284 	return -EIO;  in max9611_read_csa_voltage()
300 		switch (chan->address) {  in max9611_read_raw()
305 				return -EINVAL;  in max9611_read_raw()
314 				return -EINVAL;  in max9611_read_raw()
330 		switch (chan->address) {  in max9611_read_raw()
347 		switch (chan->address) {  in max9611_read_raw()
350 			 * processed (mV): (raw - offset) * LSB (nV) / 10^6  in max9611_read_raw()
358 				return -EINVAL;  in max9611_read_raw()
362 			adc_data -= csa_gain[CSA_GAIN_OFFS_RAW];  in max9611_read_raw()
374 				return -EINVAL;  in max9611_read_raw()
378 			adc_data -= csa_gain[CSA_GAIN_OFFS_RAW];  in max9611_read_raw()
381 			*val2 = dev->shunt_resistor_uohm;  in max9611_read_raw()
393 				return -EINVAL;  in max9611_read_raw()
395 			adc_data -= MAX9611_CIM_OFFSET_RAW;  in max9611_read_raw()
402 				return -EINVAL;  in max9611_read_raw()
407 			adc_data -= csa_gain[CSA_GAIN_OFFS_RAW];  in max9611_read_raw()
410 			*val2 = dev->shunt_resistor_uohm;  in max9611_read_raw()
418 	return -EINVAL;  in max9611_read_raw()
428 	i = max9611->shunt_resistor_uohm / 1000000;  in max9611_shunt_resistor_show()
429 	r = max9611->shunt_resistor_uohm % 1000000;  in max9611_shunt_resistor_show()
456 	struct i2c_client *client = max9611->i2c_client;  in max9611_init()
460 	if (!i2c_check_functionality(client->adapter,  in max9611_init()
463 		dev_err(max9611->dev,  in max9611_init()
465 		return -EINVAL;  in max9611_init()
478 		dev_err(max9611->dev,  in max9611_init()
481 		return -EIO;  in max9611_init()
485 	ret = i2c_smbus_write_byte_data(max9611->i2c_client,  in max9611_init()
488 		dev_err(max9611->dev, "i2c write byte failed: 0x%2x - 0x%2x\n",  in max9611_init()
493 	ret = i2c_smbus_write_byte_data(max9611->i2c_client,  in max9611_init()
496 		dev_err(max9611->dev, "i2c write byte failed: 0x%2x - 0x%2x\n",  in max9611_init()
515 	const char * const shunt_res_prop = "shunt-resistor-micro-ohms";  in max9611_probe()
516 	const struct device_node *of_node = client->dev.of_node;  in max9611_probe()
518 		of_match_device(max9611_of_table, &client->dev);  in max9611_probe()
524 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*max9611));  in max9611_probe()
526 		return -ENOMEM;  in max9611_probe()
531 	max9611->dev		= &client->dev;  in max9611_probe()
532 	max9611->i2c_client	= client;  in max9611_probe()
533 	mutex_init(&max9611->lock);  in max9611_probe()
537 		dev_err(&client->dev,  in max9611_probe()
542 	max9611->shunt_resistor_uohm = of_shunt;  in max9611_probe()
548 	indio_dev->name		= of_id->data;  in max9611_probe()
549 	indio_dev->modes	= INDIO_DIRECT_MODE;  in max9611_probe()
550 	indio_dev->info		= &indio_info;  in max9611_probe()
551 	indio_dev->channels	= max9611_channels;  in max9611_probe()
552 	indio_dev->num_channels	= ARRAY_SIZE(max9611_channels);  in max9611_probe()
554 	return devm_iio_device_register(&client->dev, indio_dev);  in max9611_probe()